Congressional Power - The u.s. senate and foreign policy

The Senate came into its own as a foreign policy force between 1850 and
1870. For most of early American history, the House of Representatives was
the dominant actor on international matters. Talented politicians, like
Henry Clay and Albert Gallatin, bolstered the power of the lower chamber.
That the Senate conducted its debates in secret until the early 1800s
decreased its public profile. And most contentious issues regarding both
domestic and foreign policy—such as the War of 1812 and the
Missouri Compromise—originated in the House.

In the 1830s the Senate began its golden age, peopled by the "great
triumvirate" of Clay, Daniel Webster, and John Calhoun. But it was
not until the end of the Mexican War that foreign policy power shifted to
the Senate. The rise of the Republican Party, the institutional effects of
the slavery issue, and the fact that most key initiatives in 1850s foreign
policy involved powers assigned to the Senate but not the House (such as
treatymaking and confirming ambassadors) facilitated the transformation.

The final factor in this process came during and after the Civil War, when
Massachusetts Senator Charles Sumner assumed the chair of the Senate
Foreign Relations Committee. Sumner first attracted national attention
during the Mexican War, when he delivered a public speech in Boston
denouncing the conflict as immoral. He became a household name after being
caned—in the Senate chamber—by proslavery Representative
Preston Brooks.

As Foreign Relations Committee chair, Sumner demonstrated his political
skills, showing how he could use the institutional powers of the Senate to
rally support even from colleagues that did not necessarily share his
approach to international affairs. Sumner most made his influence felt in
1870, when he almost single-handedly blocked President Ulysses S.
Grant's treaty to annex the Dominican Republic. Future Foreign
Relations Committee chairs of both parties—figures such as Augustus
Bacon, Henry Cabot Lodge, William Borah, Arthur Vandenberg, and J. William
Fulbright—built on Sumner's precedents.